1. Field of the Invention
The present invention relates to a hardness tester.
2. Description of Related Art
Generally, a process to increase hardness of a surface is performed on metal components using a heat process in order to improve mechanical characteristics sought for the components. Then, a hardness test is performed to evaluate whether the hardness of the surface has attained the required hardness or whether a specified hardness has been obtained to a specific depth from the surface using the heat process.
Conventionally, hardness testing methods of a pressing type are well known, such as the Vickers hardness test and the Knoop hardness test, which employ a hardness tester in which an indenter having a planar polygonal shape is pressed against a surface of a sample, then a degree of hardness of the sample is measured from a length of a diagonal line in a resulting polygonal indentation in the sample surface. Such hardness testing methods are widely used in evaluating mechanical characteristics of metallic materials (see, e.g., Japanese Patent Laid-open Publication No. 2004-286541).
As is commonly known, the Vickers hardness test employs a quadrangular pyramid diamond indenter and indicates the degree of hardness by a relationship between an average value for the length of the two diagonal lines of the quadrangular pyramid indentation formed in the surface of the sample and a pressing load of the indenter on the sample. The Knoop hardness test employs a rhomboid pyramid diamond indenter and indicates the degree of hardness by a relationship between the length of the longer of the diagonal lines of the rhomboid pyramid indentation formed in the surface of the sample and the pressing load of the indenter on the sample.
Typically, when the hardness of a metal component (hereafter referred to as a sample) is evaluated with the hardness tester, a user determines a test position on the sample ahead of time, displaces an XY stage to position the sample such that an indentation will be formed in the desired test position, then performs a hardness testing process. As shown in FIG. 10, the test positions P are frequently specified at a predetermined pitch along straight lines L1, L2, and so on, which are oriented from an edge of a sample S toward a horizontal-direction interior of the sample S. Moreover, a shape of the sample S is complex. Therefore, the test positions P are specified along the straight lines L1, L2, and so on, which are oriented in various directions.
In the hardness tester that includes an automatically drive-controlled XY stage, a layout of the test positions P is plotted on a PC. When positioning the sample S, an amount of displacement necessary to dispose the desired test positions P in a position where the indentation will be formed is computed automatically by the PC. The XY stage is thus automatically displaced to position the sample S.
However, when performing the hardness test with the hardness tester that includes a manual XY stage, the user must compute the amount of displacement by him- or herself, thus incurring time and effort. When the XY stage is manually displaced, an amount of displacement of the XY stage cannot be readily recognized. Therefore, work to displace the XY stage by the calculated amount of displacement is difficult.